Trauma‐associated human neutrophil alterations revealed by comparative proteomics profiling

Abstract

PURPOSE Polymorphonuclear neutrophils (PMNs) play an important role in mediating the innate immune response after severe traumatic injury; however, the cellular proteome response to traumatic condition is still largely unknown. EXPERIMENTAL DESIGN We applied 2D-LC-MS/MS based shotgun proteomics to perform comparative proteome profiling of human PMNs from severe trauma patients and healthy controls. RESULTS A total of 197 out of ~2500 proteins (being identified with at least two peptides) were observed with significant abundance changes following the injury. The proteomics data were further compared with transcriptomics data for the same genes obtained from an independent patient cohort. The comparison showed that the protein abundance changes for the majority of proteins were consistent with the mRNA abundance changes in terms of directions of changes. Moreover, increased protein secretion was suggested as one of the mechanisms contributing to the observed discrepancy between protein and mRNA abundance changes. Functional analyses of the altered proteins showed that many of these proteins were involved in immune response, protein biosynthesis, protein transport, NRF2-mediated oxidative stress response, the ubiquitin-proteasome system, and apoptosis pathways. CONCLUSIONS AND CLINICAL RELEVANCE Our data suggest increased neutrophil activation and inhibited neutrophil apoptosis in response to trauma. The study not only reveals an overall picture of functional neutrophil response to trauma at the proteome level, but also provides a rich proteomics data resource of trauma-associated changes in the neutrophil that will be valuable for further studies of the functions of individual proteins in PMNs.

The impact of trauma on neutrophil function

“…Examples of these include the recent description of trauma-induced changes in the composition of the circulating neutrophil pool [16] and the observation that trauma serves as a stimulus for the generation of neutrophil extracellular traps [17]. Alongside these findings, it has become apparent through the use of proteomics and microRNA profiling that trauma has a significant impact upon neutrophil signalling [18][19][20]. In this section, we review the findings of the most recent studies to have investigated trauma-induced changes in neutrophil biology.…”

“…In addition, an up-regulation of proteins with potential anti-apoptotic properties (e.g. caspase-1, cyclin-dependent kinase 2 and protein kinase B) was observed and accompanied by a significant down-regulation of proteins with potential pro-apoptotic properties [19]. Such changes would promote neutrophil survival and thus may contribute to the extended half-life of neutrophils following trauma [6,49,50].…”

“…Of these, Zhou et al [19] compared the proteomic profile of neutrophils from five healthy donors and five severely injured subjects and reported a trauma-induced alteration in the abundance of 197 proteins, 144 of which were up-regulated and 53 down-regulated. Analysis revealed proteins that were significantly up-regulated included those involved in interleukin signalling, chemokine signalling and pattern recognition [19], which would be predicted to result in increased neutrophil reactivity. In addition, an up-regulation of proteins with potential anti-apoptotic properties (e.g.…”

“…Two independent groups have recently investigated the impact of trauma on the neutrophil proteome [19,20]. Of these, Zhou et al [19] compared the proteomic profile of neutrophils from five healthy donors and five severely injured subjects and reported a trauma-induced alteration in the abundance of 197 proteins, 144 of which were up-regulated and 53 down-regulated.…”

“…To ascertain whether alterations to signalling pathways may underlie trauma-induced changes in neutrophil biology, comparative proteomics and microRNA (miRNA) profiling have been performed on neutrophils isolated from healthy controls and injured subjects [18][19][20]. MicroRNAs (miRNAs) are evolutionary conserved, small non-coding RNA molecules that assist in post transcriptional regulation [55].…”